Rhizarthrosis: An Increasingly Common Lesion

What is rhizarthrosis? It's a degenerative condition in the thumb and can be very painful.

Reviewed and approved by el médico Diego Pereira.

Written by Josberth Johan Benitez Colmenares

Last update: 17 January, 2023

Rhizarthrosis, also known as osteoarthritis of the trapeziometacarpal joint, carpometacarpal osteoarthritis of the thumb, or arthritis of the basal joint of the thumb, is one of the most common degenerative joint diseases of the hand.

According to some estimates, it affects up to 36% of older adults, although it isn’t always accompanied by obvious symptoms.

This osteoarthritis of the trapeziometacarpal joint occurs progressively, and it’s degenerative. It’s more common in older people, and this is due to natural wear and tear that occurs over time.

However, some habits related to the excessive use of the thumb can encourage its development. This is the reason for the growing increase in rhizarthrosis diagnoses in young people.

Symptoms of rhizarthrosis

Rhizarthrosis is the wear and tear of the basilar joint. This is the joint located between the trapezius bone in the wrist and the metacarpal bone in the thumb. This is a very common injury, and one that is manifested by continued use of the said joint.

Its most characteristic symptom is pain when extending the joint. For example, when pinching or holding an object strongly.

Not all people experience this symptom, although it’s by far the most common. In fact, it’s estimated that only 28% of people develop particularly severe pain. As we already stated, it’s a degenerative disease, so the pain increases as the years go by. The condition typically occurs as follows:

• Pain at the base of the thumb when moving it.
• Pain when applying pressure to the base of the thumb.
• Loss of strength in the thumb.
• Problems when carrying out activities that involve the use of the thumb (holding a cup of coffee, tying a knot, using a cellphone and so on).
• Swelling on the outside of the thumb.
• Thumb deformity (only in the more advanced stages).

As the years go by, the disease can be extremely debilitating and incapacitating in terms of the use of the thumb. In these situations, patients may experience pain even when at rest (when they don’t use the joint). Usually, this occurs only after the age of 60, although it all depends on the level of wear.

Causes of rhizarthrosis

As the researchers note, middle-aged postmenopausal women and elderly women are most affected by rhizarthrosis. In principle, most cases are idiopathic in nature.

However, excessive use of the joint in high-impact activities or movements may be behind the increasing increase in diagnoses.

Evidence suggests that occupations that involve repetitive use of the thumb and manual jobs that don’t have enough breaks during the day are a risk factor for its development.

Typing on a computer, the excessive use of cellphones, tablets, and other devices, and some intensive exercises that put pressure on the thumb (such as calisthenics) are some triggers for rhizarthrosis.

Physiologically, the laxity of the ligaments surrounding the joint is thought to be the catalyst for the condition.

Its laxity results in the misalignment of the bones of the joints due to instability. As a consequence, the bones rub against each other and progressive degeneration of the cartilage occurs.

Diagnosis of rhizarthrosis

Rhizarthrosis can be diagnosed clinically based on an assessment of symptoms, the affected area, and a review of the patient’s history.

As an adjunct, posteroanterior, lateral, and oblique radiographs of the CMC joint of the thumb are taken. These are considered the standard imaging tests to confirm the condition and rule out other possible explanations.

During the diagnosis, the specialist will classify the condition based on its progression. To do this, they will use a range from 1 to 4,where 1 is the mildest form and 4 the most severe. The initial phases don’t usually produce symptoms, and the patients who go to the doctor do so when the condition has already progressed considerably.

Treatment options

There’s currently no cure for rhizarthrosis. However, there are several therapies available to address pain and restore thumb strength and flexibility. In principle, the two types are conservative and surgical alternatives.

Given the high rates of failure reported in surgical interventions, conservative therapies are considered the first option.

Manual therapies are considered the gold standard when it comes to addressing symptoms in a conventional way. Among these are physiotherapy exercises, massages, and strengthening exercises. These can help in the short and medium term to relieve pain, as well as stop the progression of the disease.

On the other hand, intra-articular corticosteroid injections and thumb splinting may also be considered. When none of this reports a substantial improvement in the patient, surgical interventions are considered.

For patients with grades 1 and 2, palmar carpal ligament reconstruction and metacarpal extension osteotomy are considered. For those with grades 2 (late), 3, and 4, possibilities are a simple trapeziectomy or trapeziectomy with ligament reconstruction and tendon interposition.

Treatment options are chosen based on the patient’s condition. In all cases, it’s accompanied by counseling regarding lifestyle habits.

The most important thing of all is to avoid activities or movements that require use of the thumb joint. Consult with your specialist about what alternatives are available to you in order to deal with the symptoms and improve your overall well-being.